The nonequilibrium Green´s functions method and descendants: Ways to avoid and to go

We present a novel quantum transport method that follows the non-equilibrium Green´s function framework but sidesteps the iterative calculation of lesser self energies by replacing them by global relaxation parameters. This method generalizes the so-called Buttiker probe model but takes into account all relevant individual scattering mechanisms. It is orders of magnitude more efficient than a fully self-consistent non-equilibrium Green´s function calculation for realistic devices, yet accurately reproduces the results of the later method.